Which of the following best explains the general increase in electronegativity…
CHEMISTRY · Single correct · A Level · Chemistry · Periodicity and periodic trends · Periodicity and periodic trends
Problem
Which of the following best explains the general increase in electronegativity observed when moving from Na to Cl across period 3 of the periodic table?
(a) The shielding effect from core electrons increases markedly across the period, allowing the nucleus to attract bonding electrons more strongly.
(b) Because the number of valence electrons increases from 1 to 7, these atoms have a greater "need" to gain electrons to complete an octet, so their electronegativity rises.
(c) The effective nuclear charge experienced by the valence electrons increases while shielding remains nearly constant, strengthening nuclear attraction.
(d) Atomic radius decreases across the period, so bonding electrons are held closer to the nucleus and therefore more strongly attracted.